Solve the Puzzle questions

Page
3

5

The green region (5 students) is denoted by

M G, which is read, “M intersect G”

or “the intersection of M and G.”

Slide 23

U

M

G

We know that #(U) = 30, #(M) = 17, and #(G) = 12.

Let’s have a quick review,

how do you say the following:

5

M G

A) “the intersection of M and G”

B) “M intersect G”

C) “M and G together”

D) both choices A & B

Slide 24

Great Job!

A mnemonic device for remembering that the symbol means intersection,

is thinking that the symbol

looks like the letter n for

intersection!

Slide 25

U

M

G

We know that #(U) = 30, #(M) = 17, and #(G) = 12.

5

And remember that the green region has 5 students in it, who watch MTV and play video games, which is #(M G) = 5

So if circle M has 17 in all, but 5 of them are in the intersection area, how many are in just the blue area?

17

22

12

27

Slide 26

U

M

G

We know that #(U) = 30, #(M) = 17, and #(G) = 12.

5

What about the yellow area?

If circle G has 12 total, how many are in just

the yellow area?

7

12

24

17

We also know that #(M G) = 5

12

Slide 27

U

M

G

5

So now we have all three areas filled in!

12

7

Let’s try those questions from the start of the investigation one more time .

Slide 28

U

M

G

5

How many students watch MTV only, no video games?

12

7

5

12

17

7

24

6

Slide 29

U

M

G

5

How many students play video games only, no MTV?

12

7

5

12

17

7

24

6

Slide 30

U

M

G

5

How many students play video games or watch MTV (possibly both)?

12

7

5

12

17

7

24

6

Slide 31

U

M

G

5

Our three regions add to 24.

The 24 are all the students who play MTV or play video games (or both!)

12

7

12

+

5

+

7

=

24

Slide 32

U

M

G

5

12

7

We have a symbol in math that describes this joining of regions. It is called union and looks like the letter U.